Magnetically controlled gaseous discharge device



Feb. 27, 1940. P, L, 'SPENCER 2,191,595

MAGNETICALLY CONTROLLED GASEOUS DISCHARGE DEVICE Filed Feb. 11, 1938 2Sheets-Sheet l mam? PE/FC y Z. SPENCER Feb. 27, 1940. P. L. SPENCER2,191,595

MAGNETICALLY CONTROLLED GASEOUS DISCHARGE DEVICE Filed Feb. 11, 1938 2Sheets-Sheet 2 A 0.105 TABL E fiEcT/F/me 26 PHASE SH/FT ADJUSTABLE o- 2flows TABLE RES/5 70B 26 171106721 707 PERCY L. SPENCER "UNITED STATESPATENT OFFICE Y a I f 7 1,101,351," I I manna-romp oon'raomnn Games I.msomonnmoa Percy 1L. Spencer, West Romany Mass; assign'or' v toRaytheo'n Manufacturin Oomn nmNewton, Massua' corporationofll'elaware,

Application '11, .1933, Ho. 190m This invention relates to controlled'gaseous dispassing through the electrode 5, it is intended that chargedevices, and more particularly tol-suclii-v these expressions shallinclude those conditionsin devices in which the time of'starting of anionwhich the electrode partially surrounds the izing discharge betweenthe electrodes is' condischarge path to an extent sufficient toaccomtrolled by means of a magnetic fleld. Y plish-the type of controlhereinafter described. 5 I

An object of my invention is to provide such The envelope .I is providedwith a reentrant a magnetically controlled tube which is capable stem 8at each end thereof, each of which stems of conducting and controllinglarge values of cursupports one of the cathodes 4 and one of the rentsflowing in either or both directions through intermediate electrodes 5.Each cathode 4 prefsaid tube under substantial applied voltages. erably'consists of a hollow member 9, preferably Another object of thisinvention is to produce of some. metal such as nickel provided with asuch a device which is flexible in control and; plurality of internalradially disposed metal fins which is adapted to accomplish a widevariety of Ill. The metal fins and also the interior of the controloperations. hollow member 9 are coated with an electron- II Theforegoing and other objects of my invenemissive material, such as, forexample, alkaline ll tionwill be best understood from the followingearth oxides. In order to heat the coated surdescription of anexempliflcation thereof, referfaces of the cathode 4 to temperature oftherence being had to the accompanying drawings mionic emission, aheating filament II is disposed wherein: within the hollow member 9. Theheating filam Fig. l is a cross-sectional view of one embodiment I I mayconsist of'a single helix of a re- Q ment of my invention showing mynovel discharge fractory conductor, such as tungsten, and is electubetogether with a diagrammatic representatrically connected at its upperend to the hollow tion of a circuit whch may be used therewith; member 9by being welded} to one of the fins I0. and} In order to preventexcessive radiation of heat Figs. 2, 3 and 4 are diagrammaticrepresentafrom the hollow member 9, it is surrounded by :5 tions ofvarious types of control current supply means of a heat shield I2. Eachcathode asfor Fig. 1. sembly 4 is supported on the stem 8 by means InFig. 1, I represents a hermetically sealed of a pair of conductingstandards I3 which are envelope, preferably of glass, having enlargedsealed in the press 8. One of the standards I3 end chambers 2 at eachend thereof, said enis sealed] through said press so as to provide an 30larged chambers being connected by a tubular external electricalconnection to the cathode 4. intermediate section 3. In each enlargedcham- The lower end of the heating filament II is pro her 2 is mounted acathode 4. Adjacent each vided with a lead I4 which is likewise sealedcathode 4 and surrounding the discharge path through the press 8 so asto provide an external terminating at said electrodes is an intermediateelectrical connection thereto. In the drawings 5 control electrode 5.The electrode 5 is preferit will be seen that the cathode 4 at therightably made of non-magnetic material, and" may hand end is shown incross-section. However, it comprise a cylinder of sheet metal, such asnonis to be understood that the cathode 4 at the left magnetic nickel,tantalum or carbon. Since each is of identically the same structure asthat shown a, electrode 5 will also operate as an anode, as will at theright-hand end. be hereinafter described, it is preferred that the Inorder to support each of the intermediate material of which theelectrode 5 is constituted electrodes 5 in position adjacent eachcathode 4, shall be relatively refractory. The electrodes 5, eachelectrode 5 is provided with a pair of conas shown, are each providedwith an end plate 6 ducting standards I5, which are sealed in the 4|having a relatively large opening 1 passing thererespective press 8. Ineach case one of the standthrough. The opening I therefore permits adisards I5 is sealed through its press 8 so as to procharge to pass fromeach cathode 4 through the vide an external electrical connection to itsasadjacent opening 1 to the opposite electrode 5 as sociated electrode5. an anode. Of course each electrode 5 may be of The envelope Icontaining the construction as a any other suitable form, and it ispossible to make described above, after being thoroughly evacuated it sothat it does not completely surround the in accordance with the usualpractice, is filled discharge path but only partially surrounds it. withsome suitable ionizable medium. This In the specification and claims,whenever the medium maybe ametallic vapor, such as mercury electrode 5is defined as surrounding the disvapor, or a gas, such as one of thenoble gases,

charge path or when the discharge is, described as or a mixture thereof.When mercury vapor is u used, pressures in the range of one to onehundred microns are preferred, while in the case of a noble gas, such asargon, a pressure of the order of one millimeter or less is preferred.In any event, the gas preferably is of a suitable value so that when adischarge across the gas or vapor becomes ionized, a current fiows at arelatively low voltage drop.

In order to supply power to the device, there is provided a supplytransformer l6 having a primary I1 and a secondary IS. The primary I1 isadapted to be connected to some suitable source of alternating current.A conductor l9 connects one end of the secondary l8 to one of the leadsI3, and thus to one of the cathodes 4, for example the right-handcathode. A conductor 20 extends from the opposite end of the secondaryl8 to a load{ 2|. The other side of the load is connected by means of alead 22 to the other conductor l3, and thus to the other cathode 4. Eachpair of conductors I3 and I4 is adapted to be connected to a suitablesource of heating current, whereby the heating filament II in each caseis raised to its operating temperature. The external conductor I5 ofeach intermediate electrode 5 is connected} by means of a conductor I5to the adjacent lead I3, and in this way each intermediate electrode 5is connected to its adjacent cathode 4.

Upon supplying heating current to each pair of conductors l3 and [4, thefilament II and consequently the coated surfaces of each cathode 4 willbe raised to a temperature at which said coated surfaces emit a copioussupply of electrons thermionically. -As each cathode 4 becomes negative,the electrode 5 associated with the opposite cathode 4 will becomepositive, and thus will act as an anode with respect to the negativecathode. Under these conditions, the electrons emitted from the negativecathode will flow through its adjacent electrode 5, through itsdischarge opening I to the opposite electrode 5. This flow of electronswill produce intense ionization of the gas within the envelope, andcurrent at a relatively low voltage drop will flow between the negativecathode 4 and the positive electrode 5. Since these conditions arereversed with each reversal of the applied voltage, it will be seen thatcurrents will flow through the tube l in both directions, and analternating current will be delivered to the load 2|.

As more fully described and claimed in my copending application, SerialNo. 612,235, filed May 19, 1932, now Patent No. 2,124,682, for animprovement in Electrical gaseous discharge devices, a discharge of thetype which I have described above is prevented from starting when amagnetic field of a predetermined, magnitude, intercepting the directionof said discharge, is impressed across the space within the intermediateelectrode 5. This transverse magnetic field may be applied in anysuitable manner. For example, I have shown a pair of magnetic polepieces 23 disposed on opposite sides of each intermediate electrodie 5outside of the tubular portion 3. Each pair of pole pieces 23 may formpart of a unitary core structure. In order to energize each of said corestructures and said magnetic pole pieces, energizing or control coils 24are provided for each of the pole pieces 23. The energizing coils 24associated with each pair of pole pieces 23 are fed with current througha control device 25 which may be energized from any suitable source. Asindicated inthe drawings, this source may be the transformer Hi. In thiscase a pair of conductors 28 are provided connecting the input to eachcontrol device 25 in parallel, and a pair of conductors 21 connect thetwo leads 28 to opposite sides of the secondary winding l8. Although -Ihave described each intermediate electrode 5 as being provided with aseparate pair of pole pieces, a single pair of pole pieces could. beprovided if such a magnetic structure were made sufliciently large toset up a transverse magnetic field in the space within both of theintermediate electrodes 5. However, in the interest of more flexiblecontrol, the construction as described in the drawings is preferred.

When the device is energized, as described above, and a discharge tendsto flow alternately from each cathode 4 to the opposite electrode 5, itwill be seen that such a discharge must pass through the intermediateelectrode adjacent its associated cathode. Under these conditions, whena magnetic field is set up by each pair of pole pieces 23 interceptingthe discharge passing through said intermediate electrode 5, theinitiation of the discharge will be delayed for a predetermined part ofthe voltage cycle, depending upon the relative value of the magneticfield and the applied voltage. In most instances the discharge can beconsidered as being initiated whenever the magnetic field falls tosubstantially a zero value. In order to accomplish different types ofcontrol, the control devices 25 may be constructed, for example, tosupply to the coils 24 a controllable direct current, as indicated inFig. 2. Also each control device 25 might be constructed to supply tothe energizing coils 24 a variable current of the same frequency as thatsupplied to the transformer l6. One arrangement might be that indicatedin Fig. 3 wherein each control device 25 would} be constructed so as toshift the phase of the current supplied to the coils 24 with respect tothe voltage supplied to the transformer l6. Another arrangement might beto construct each control device 25 as an adjustable resistor, asindicated in Fig. 4, whereby alternating current varying in magnitudepending application mentioned above, and also i in my copendingapplication, Serial No. 188,887, filed February 5, 1938, for animprovement in Controlled gaseous discharge devices. Briefly these typesof controls might be summarized as follows.- When variable amounts ofdirect current are supplied to the coils 24, (Fig. 2) alternatingcurrents will flow in the load 2| and will be controlled in magnitude.When alternating current varying in phase (Fig. 3) or magnitude (Fig. 4)is supplied to the coils 24, likewise alternating current of varyingmagnitude will be supplied to the load 2|. One type of control is thatin which magnetic pole pieces 23 are biased with a certain amount ofunidirectional flux, either by being constructed as a permanent magnetor by having the coils 24 supplied with a direct current component, andin addition being supplied with an alternating component of flux byfeeding an alternating component of current to the coils 24. Under theseconditions, the device may be made to supply rectified current to theload 2|, the polarity of said. direct current depending upon the phaserelationship of the alternating current component of the flux withrespect tothe voltage applied to the tube. Fur- 75 thermore, under theseconditions, variation in said phase relationship will produce variationin the magnitude of the direct current supplied to the load.

This invention is not limited to the particular details of constructionor operation as described above as many equivalents will suggest themselves to those skilled in the art. For example, the electrodes can takea variety 01 forms. Furthermore, various combinations of circuits andcontrols may be impressed upon the tube, producing a wide variety ofdevices of operation. It is accordingly desired, therefore, that theequivalents which come within the scope of the appended claims beconsidered as being included within the scope of the invention.

What is claimed is:

1. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two cathodes, twointermediate electrodes, each adjacent one of said cathodes, eachintermediate electrode having a discharge passage through it in thedirection of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other of said intermediate electrodes as an anode, andmeans for producing a magnetic field which is transverse to thedirection of each of said discharges adjacent each intermediateelectrode.

2. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two thermionic oathodes,two intermediate electrodes, each adjacent one of said cathodes, eachintermediate electrode having a discharge passage through it in thedirection of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other of said intermediate electrodes as an anode, andmeans for producing a magnetic field which is transverse to thedirection of each oi said discharges adjacent each intermediateelectrode.

3. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two thermionic cathodes,two intermediate electrodes, each adjacent one 01 said cathodes, each ofsaid intermediate electrodes being connected to its adjacent cathode,each intermediate electrode having a discharge passage through it in thedirection of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other of said intermediate electrodes as an anode, andmeans for producing a magnetic field which is transverse to thedirection of each of said discharges adjacent each intermediateelectrode.

4. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two thermionic cathodes,two intermediate electrodes, each adjacent one of said cathodes, each ofsaid intermediate electrodes being connected to its adjacent cathode,each intermediate electrode having a dis charge passage through it inthe direction of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other oi! said intermediate electrodes as an anode,means for. producing a magnetic field which is transverse to thedirection of each of said discharges adjacent each intermediateelectrode.

5. In combination, an electrical space dis charge device comprising anenvelope containing an ionizable atmosphere, two thermionic odes, twointermediate electrodes, each adjacent one of said cathodes, eachintermediate electrode having a discharge passage through it in thedirection of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other of said intermediate electrodes as an anode,means for producing a magnetic field which is transverse to thedirection of each of said discharges adjacent each intermediateelectrode, and means for controlling said magnetic fields forcontrolling said discharges.

6. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two thermionic cathodes,two intermediate electrodes, each adjacent one of said cathodes, eachintermediate electrode having a discharge passage through it in thedirection of the other of said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other of said intermediate electrodes as an anode,means for producing a magnetic field which is transverse to thedirection of each or said discharges adjacent each intermediateelectrode, and means for controlling the magnitude of said magneticfields for controlling said discharges.

I. In combination, an electrical space discharge device comprising anenvelope containing an ionizable atmosphere, two thermionic cathodes,two intermediate electrodes, each adjacent one of said cathodes, each ofsaid intermediateelectrodes being connected to its adjacent cathode,each intermediate electrode having a discharge passage through it in thedirection of the other 01' said intermediate electrodes, whereby adischarge may pass from each cathode past one of said intermediateelectrodes to the other 01' said intermediate electrodes as an anode,means for producing a varying magnetic field which is transverse to thedirection of each of said discharges adjacent each intermediateelectrode, means for connecting a source of alternating current betweensaid cathodes, and means for controlling the phase angles between saidmagnetic fields and said source for controlling said discharges.

PERGY L. SPENCER.

